Eoege hammer



Dec. 17, 1929. w HAGMAN 1,740,341

FORGE HAMMER Filed Feb. 11, 1925 2 Sheets-Sheet 1 D 1929- w. J. HAGMAN1,740,341

FORGE HAMMER Filed Feb. 11, 1925 2 Sheets-Sheet. 2

Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE ronen HAMMERApplication filed February 11, 1925.

My invention relates to hammers and it has particular relation tocushioning apparatus therefor.

Inasmuch as the usual forge hammer has a vertically reciprocal pistonrod with a variable stroke, the length of which stroke is subject to thecontrol of the operator, it often happens that through carelessness orpoor judgment on the part of said operator, the

piston is driven against the cylinder head, thus causing it to shatterand the fragments to be projected in the air.

Moreover, piston rods have been known to break loose from the rams orcross-heads, or

the rods to snap apart at some point in their length. Should either ofthese accidents occur while pressure is applied to the underside of thepiston, a quick upward drive of the piston results and the cylinder headis shattered. Under some conditions, even the piston itself may bethrown from the hammer.

The danger accompanying such accidents is manifest, and, in a measure,has been guarded against by various kinds of buffers but these buttershave been of the resilient type and are eli'ective only under relativelylight loads.

7 Another method of guarding against such accidents involves thepressing or cushioning of the gases above the piston, but to obtain asuitable cushion within the hammer cylinder in the ordinary manner wouldne cessitate a considerable extension of the cylinder above the uppersteam port in order to provide for a reasonable travel of the pistonafter it has closed said port. Such addition to the cylinder, however,would be wasteful of the steam or compressed air or other actuatingfluid medium.

7 An object of my invention, therefore, is to provide a suitablecushioning device that shall avoid the abovenoted disadvantages 4 andyet be simple in design and efficient and reliable in operation. To thisend, I provide a mechanical choke to the exhaust gases whichautomatically comes into an effective position when needed and which ismovable into an ineffective position out of the path Serial N0. 8,461.

of travel of the piston when it is not required and conditions arenormal.

With these and other objects and applica-- tions in mind, myinvention-further consists in the details of construction and operationand arrangement, hereinafter described and claimed and illustrated inthe accompanying drawing, wherein Fig. 1 is a side elevational viewpartially in section of a forge hammer embodying my invention; and

Fig. 2 is an enlarged detail sectional view of the cushioning apparatusshown in Fig. 1.

In the illustrated embodiment of my invention shown in the drawing, aforge hammer 1 comprises a frame 2 which provides ways 3 and 4 for avertically movable hammer 5, a lower end of which carries a die 6adapted to co-act with a second die 7 carried on a die block 8 whichrests on an anvil 9.

An upper end of the hammer 1 is secured to a piston-rod 11. The latterissecured to a lower face 12 of a main piston 13" which is verticallymovable in a main hammer cylinder 14 supported in the upper portion ofthe frame 2. V

A lower end 15 of the main cylinder 14 is provided with a lower port 16which communicates by means of a passage 17 with one port 18 of a valvechest 19. A second port 21 of the valve chest 19 communicates by meansof a passage 22 with an upper end 23 of the main cylinder 14, as willappear more fully hereafter. An intermediate port 24 communicates with apressure fluid inlet opening 25. The pressure fluid may, for example, besteam or compressed air or other motive fluid.

The valve chest 19 may be designed to receive a piston valve 26 of usualconstruction, and it may be operated by means of a valve rod 27 whichextends from the valve chest 19. The piston valve 26 may comprise atubular element 28, opposite ends of which are respectively adapted toclose the ports 9 18 and 21 when in the mid-position shown in Fig. 1.The central portion of the tubular element 28 is of smaller diameterthan the end portions which cooperate with the ports 18 and 21, wherebya passagemay be tubular element 28 is moved upwardly from.

the position shown in Fig. 1, the port 18 is uncovered, thus connecting,the lower end portion of the main cylinder 14 to the valve chest exhaustpassage129, as will be readily apparent to those skilled in the art.

,As above-noted, my a invention contemplatesa mechanical choke 30, whichshall be operable to trap the exhaust fluid or gases in the upper end 23of the main cylinder 14 should the operator permit the piston 13 to moveupwardly in the main, cylinder 14 beyond a predetermined extent, thuscausing the piston 13 to be, quickly brought to rest without a violentshock or the breaking of relate'd.,parts. In the] drawings, I have shownone form of mechanical choke for accomplishing the afore-mentioneddesired resultsand it comprises avertically extending casing or cylinder31, a lowerend 32 of which is formed to constitute the upper head of themain cylinder 14 and is secured thereto by bolts 33 and 34.

Atubular plunger 35 is mounted for vertical "movement in a perforation36 in the lower end 32 of. the auxiliar cylinder 31, and it has a lower"open end 3 ,constituting the upper port of the ma cylinder '14. The.

port 37 is adapted to be closed by the upper side 38 of the main piston13 when'thelatter I'nov'es upward at a dangerous speed beyond apredetermined point, that is, beyond a point where "the application offluicl pres- V sure to the upper side 38 of the main "piston 1.3'wi11check the upward movement of the same before it strikes the piston head,all as willsappear hereinafter. H Y

fl heupp'er end of thetubularplunger '35 is closed by means of a plug 41which secured in threaded engagement therewith, as illustrated. Thefreeen'd of the plug 41 is formed to constitute a pisto'nI42.- In orderthat the extent or movement of the tubular plunger-'35 *iut'b the upperend portion 23 of the niain cylinder 14jin-a'y be Il'or- Inall'y limitedto that shown in Fig.1, inwardly extending annular "flange 43 is formeron the inner side offthe *au'x'iliary cylinder 31-, saidhangconstituting fafstop ferti e lowered-gr, or are auxiliar piston :42.f'ljh'eau'xil iary cylinder 31 i's t us divided by fthe auxi'liarypiston "42 into "upper and lowerportions .44'aiid 45 having ports 46'and '47,. respectively. The up er port 46' tively.

plunger, 35 into the main substantially simultaneously with the iipwardmovement of the main piston 13. The motive fluid on the upper side ofthe auxiliary piston42 also provides a cushioning effect to the verticalmovement of the piston 42 and the ,plunger 35 due to the main piston 13striking said plungr'sa p A plurality of,orifices 50, areformedjn theupper endof the tubular plunger 35, whereby the port 47 which ispositioned the lower end portion45 of the auxiliary y n r 1 may b cum n10 5 3,v 0 1 munication with the open end of vthe tubular plunger 35. Thepassage 22 leading from theport 21 of the valve chest 19 to the lowerport 47 is thus in. continuous coinmunication withadjacentsides of themain and auxiliary pistons 13 and 42, respeclVhen the operator desiresto; raise the die 6 out of engagement with the dise Z, the tuhularelement 28 is moved downwardly from the position shown in ll so as tointerconnect the ports 24 and18'. Fluid spressu re gis ppli d e i n eidew 9f pisa sing; an upward move e a th same. Intheprior art ,machinesa sab'ove} 9t Li th s em n a be zehe l by further actuating the tubularelement 28;,so as to cause 'a supply of fluid pressure tothe upper sideof thepiston 13, while -siinultane ously exhausting the vfluid pressurefrom the underside thereof. The inherent disadvantages oi this method,of, "control are readily apparent to those skilled in the art,

t In accordance with my invention, as hereinabove noted, t fluidpressure is supplied through passage 48 to theupper] side of theauxiliary piston 42,si nultaneously with the application of th e fluidpressure to theglower side of thepiston 13, with the result that thepiston 42 is actuateddownwardly into engagement with the annualflange43, as

shown invFigulre 1, whilethe piston 13 is actuated upwardly. I p A v,

, Then the dpe'rator desires to reverse "the meanest "or thepisto'n13,the tubular e ement is actuated 'ipivifrdly so asto uncover the discharge part '18, and atria permit the erits "to exhaust froiih theun ders'ide 5f "the piston 13 "through as tuna passa e 29. The apies-a.me'vemut the aiminelem-em 2's just noted ais -serves to connect thefluid supply fopening 25 to the port 4'7, with the result that fluidpressure is supplied to the upper side pf the fiiain piston 13 and tothe loWe'rside of'theauxiliary piston 12, causing an upward movement ofthe latter and a downward movement of the former. The withdrawal of thelower end portion of the tubular plunger 35 from the path of travel ofthe upwardly moving piston 13 is an important feature of my invention,inasmuch as it prevents an unnecessary striking of the tubular plunger35 by the main piston 13. The movement of the piston 13 being nowreversed, the die 6 is moved downwardly to accomplish the work desired.

Should the operator maintain the fluid pressure on the underside 12 ofthe main piston 13 so long that the subsequent application of the fluidpressure to the upper side thereof is not suflicient to prevent thepiston 13 from striking the upper end of the main cylinder ll, or whatis equivalent thereto, should the piston 13 become detached from the ram5, the open end 37 of the safety plunger 35 closed by the adjacent face38 of the piston 13, trapping the exhaust fluid in the upper end of themain cylinder 14. As

- the piston 13 continues to move upwardly,

the gases are compressed, forming an elastic cushion which very quicklybrings the piston 13 to rest without a violent shock. The verticalmovement of the tubular plunger 35 is further resisted by the "force ofthe fluid pres sure acting on the upper side of the auxiliary piston 42.When it is desired again to cause a downward movement of the piston 13,the tubular element 28 is moved upwardly from the position of Fig. 1 soas to permit a supply of the pressure fluid to the adjacent sides of thepistons 13 and a3, respectively.

While I have shown only one form of em bodiment of my invention, for thepurpose of describing the same and illustrating its principles ofconstruction and operation, it is apparent that various changes andmodiiications may be made therein Without departing from the spirit ofmy invention, and i desire, therefore, that only such limitations is illbe imposed thereon as are indicated in the appended claims or as aredemanded by the prior art.

1 claim:

1. In a hammer having a main cylinder provided with a main piston, apassage for conveying fluid to and from the upper end of said maincylinder, and means for controlling the flow of fluid to and from saidfluid passage; the combination therewith of a plunger reciprocallymounted at and extending into the upper end of said main cylinder, saidplunger being hollow and open at its end nearest said main piston andhaving a duct aflording communication between said opening and saidfluid passage, said plunger being adapted to have its open end engagedand the opening therein closed by said main piston, thereby preventingthe exhaust of fluid from the upper end of said main cylinder, foreffecting a compression of fluid remaining in the said upper end of saidmain cylinder, when said main piston approaches the said upper end ofsaid main cylinder beyond a predetermined point in its travel withinsaid main cylinder, the fluid from the upper end of said main cylindernormally exhausting through the opening and duct in the plunger to thesaid fluid passage when the fluid controlling means is operated. topermit the exhaust of fluid from said fluid passage; said plunger beingoperated out of the path of travel of said main piston when said fluidcontrolling means is operated. to admit fluid to said fluid passage andthrough said duct and said plunger opening into the upper end of saidmain cylinder, said operation of said plunger being effected by theforce of the fluid exerted between the main piston and the plunger.

2. In a hammer having a main cylinder provided with a main piston,passages for conveying fluid to and from the opposite ends of said maincylinder, and means for controlling the flow of fluid to and from saidpassages, the combination therewith of an auxiliary cylinder having anauxiliary piston provided with a hollow plunger extending into the upperend of said main cylinder and adapted to be engaged by said main pistonas the same approaches the upper end of said main cylinder, said hollowplunger being open at its end toward said piston and having openingscommunicating with the fluid passage for the upper end of said maincylinder. said main piston closing the open end of said hollow plungeras it approaches the upper end of the main cylinder, thereby trappingand compressing fluid in the said upper end of said main cylinder, saidhollow plunger being raised from said piston to permit fluid to flow tothe upper end of said main cylinder by said fluid exerting a forcewithin the said hollow plunger between the upper end of the main pistonand the lower end of the auxiliary piston when such fluid is admitted.to the passage conveying said fluid to the upper end of said maincylinder.

In a hammer having a main cylinder provided with a main piston, passagesfor conveying fluid t0 and from the opposite ends of said main cylinder,and means for controlling the flow of fluid to and from said passages,the combination therewith of an auxiliary cylinder having an auxiliarypiston provided with a hollow plunger extending into the upper end ofsaid main cylinder and adapted to be engaged by said main piston as thesame approaches the upper end of said main cylinder, said hollow plungerbeing open at its end toward said piston and having openingscommunicating with the fluid passage for the upper end of said maincylinder, said main piston closing the open end of said hollow plungeras it approaches the upper end of them-ain cylinder, thereby trappingand-compressing fluid in the said upper end of said main cylinder, meansfor con- 1 veying operating fluid from thelower end 5 of said maincylinder to the upper endof said auxiliary cylinder to force said hollowplunger into saidinain cylinder When said operating fluid is admitted tothe passage leading to the said lower'end of said main 1O cylinder toraise the main piston therein,

said hollow plunger being raised from said piston to permit fluid toflow to the upper end of said main cylinder by said fluid exerting aforce Within the said hollow plunger between the upper end of the mainpiston and the lower end of the auxiliary piston when such fiuid isadmitted to the passage conveying said fluid to the upper end of saidmain cylinder, and the spent fluid is permitted to flow from the lowerend of said main cylinder and from the upper end of said auxiliarycylinder, by the reverse operation of the means controlling the flow ofsaid fluids to and from said fluid passages.

WILLIAM J. HAGMAN.

